Machined parts cleaning apparatus having air control system



Oct. 15, 1963 B. RAND 3,106,928

MACHINED PARTS CLEANING APPARATUS HAVING AIR CONTROL SYSTEM Filed May 3,1962 2 Sheets-Sheet 2 INVENTOR BURTON l-FA ND ATTORNEY United StatesPatent 3,106,928 MACHINED PARTS CLEANING APPARATUS 1 HAVING AIR CGNTROLSYSTEM Burton Rand, Bala Cynwyd, Pa., assignor to Autosonics Inc,Philadelphia, Pa, a corporation of Pennsylvania Filed May 3, 1962, Ser.No. 192,115 5 Claims. (Cl. 134-49) This invention relates to a cleaningapparatus, and more particularly, to a cleaning apparatus for removinggrease and hydrocarbon deposits in addition to dirt from machined partsby treatment with solvents.

The cleaning apparatus of the present invention is an improvement overthe cleaning apparatus set forth in my prior Patent No. 3,019,800.Experience has shown that the cleaning apparatus in my above mentionedpatent adequately performs its intended function. I have now discoveredthat a cleaning apparatus of the type disclosed in my above mentionedpatent need not be provided with a top wall and that a comparableefficiency may be obtained in preventing loss of evaporated solvent whenan air control system in accordance with the present invention isincorporated therein. The air control system of the present inventionmay also be provided on other types of cleaning apparatus lacking a topWall such as the cleaning apparatus disclosed in my copendingapplication Serial No. 60,106 filed on October 3, 1960, now Patent No.3,073,323, and entitled Cleaning Apparatus.

I have discovered that an air control system may be provided on acleaning apparatus lacking a top wall regardless of whether or not theapparatus is provided with means causing the formation of a vapor zoneabove the level of the solvent. Tests performed on the apparatus in myabove mentioned patent were run with and without the air control systemof the present invention. When the air control system of the presentinvention was not utilized on a cleaning apparatus of the typeillustrated in my above mentioned patent and lacking a top wall, thepresence of vaporized solvent in the atmosphere was very noticeable.Such vaporized solvent in the atmosphere or fumes of vaporized solventconstitute a danger to operating personnel. When the air control systemof the present invention was incorporated in the cleaning apparatusdisclosed in my above mentioned patent, the presence of vaporizedsolvent in the atmosphere adjacent the cleaning apparatus wassubstantially eliminated.

In accordance with the present invention, an air control system islocated at a point close to and above the level of the liquid solvent orthe vapor zone thereabove. Conduit means are provided so that a mixtureof air and vaporized solvent may be removed from the space in theapparatus above and adjacent to the vapor zone or liquid level. Suchmixture is removed by means of a fan or pump which is coupled to theinterior of the cleaning apparatus through a condenser. The condensersepa rates the mixture into cool air and liquid solvent which isreturned to the lower portion of the cleaning apparatus. The cool air isducted to the opposite side of the cleaning apparatus and returnedthereinto.

The cool dry air which is returned by means of an uninsulated duct tothe opposite side of the cleaning apparatus is preferably returned atthe same height at "ice which the mixture is removed. There is noheating of the returned air since it is desirable to have the cool dryair settle into the cleaning apparatus rather than rise out from the topthereof as would occur if the returned air were heated. When a cleaningapparatus is provided with means causing a vapor zone above the level ofthe liquid solvent, the air control system of the present invention is asupplementary control.

It is to be emphasized that the fan or pump of the present invention isextremely small. Hence, the circulation in the air control system isconducting a small volume of air on the order of five to thirty cubicfeet per minute depending upon the size of the cleaning apparatus. Asthe size of the cleaning apparatus increases, the amount of air which ismoved by the control system of the present invention increases. In allcases, the amount of air which is being moved is barely noticeable andmay be referred to as a waft of air.

The present invention may be utilized in conjunction with cleaningapparatus of the type illustrated in my above mentioned patent orcopending application wherein localized cavitation is provided by meansof an ultrasonic transducer which generates downwardly toward the par-tsto be cleaned. In this manner, the contaminate which is removed from themachined parts cannot settle onto the transducer, but instead willsettle on the bottom wall of the cleaning apparatus. Preferably, themachined parts to be cleaned are supported in a manner so that there isno conveying apparatus between the transducers and the machined partswhich could interrupt the localized cavitation and thereby elfect'theefficiency of the ultrasonic cleaning effect.

The present invention provides an effective means for controllingdangerous or toxic fumes in such instances where a top wall on apparatusis impractical. For example, it is impractical to use a top Wall on abatch tank wherein the parts to be cleaned are lowered into and raisedfrom the tank by means of an overhead hoist.

The National Conference of Industrial Hygienists has recently reducedthe limits of toxic tolerance for degreasing solvents from 200 parts permillion to 100 parts per million. Hence, it will be seen that there is adefinite need for the present invention and that the importance,usefulness and desirability of the present invention are greater thanthey have been heretofore.

It is an object of the present invention to provide a cleaning apparatushaving an air control system.

It is another object of the present invention to provide a cleaningapparatus lacking a top wall with an air control system therebysubstantially eliminating the danger of fumes caused by vaporizedsolvent.

It is another object of the present invention to pnovide a novel aircontrol system for a cleaning apparatus lack- '50 is fixedly secured tothe shaft 42.

shown in the drawings a form which is presently preferred; it beingunderstood, however, that this invention is not limited to the precisearrangements and instrumentalities shown.

FIGURE 1 is a longitudinal sectional view of the cleaning apparatus ofthe present invention.

FIGURE 2 is a transverse sectional View taken along the lines 22 inFIGURE 1.

FIGURE 3 is a top plan view of the cleaning apparatus of the presentinvention.

Referring to the drawing in detm'l, wherein like numerals indicate likeelements, there is shown in FIGURE 1 a cleaning apparatus designatedgenerally as 1%.

The cleaning apparatus includes a housing designated generally as 12.The housing 12 includes opposite side walls 14 and 16. The side wall 14extends for the full height of the housing 12. The side wall 16 extendsup to a horizontally disposed portion 20. A side wall 18 extends fromthe horizontally disposed portion to the top of the housing 12. Thehousing 12 lacks a top wall and is provided with a bottom wall 24. Thehousing 12 also includes a front wall 22 and a rear wall 26.

A mechanical means is provided within the housing 12 to mechanicallyconvey parts to be cleaned through the housing 12. Such means includes astationary plate 28 which is supported by means of brackets 30 and 32. Apair of arcuate plates 34 and 36 are affixed to one surface of the plate28. The plate 34 has one free end 34' and a second free end 34". Theplate 36 has a free end 36' and a free end 36".

An arcuate plate 38 having an arcuate length greater than 180 degrees isspaced from and partially surrounds the plates 34 and 36. The plate 33is secured to and extends from the periphery of plate 28.

A hearing 40 is fixedly secured to the plate 28 in a central portionthereof. The bearing 40 rotatably sup ports one end of a shaft 42. Theother end of shaft 42 is rotatably supported by a bearing 44 fixedlysecured to the inner surface of wall 14. A plate 46 is fixedly securedto the shaft 42 adjacent a central portion thereof. A plate 46 isjuxtaposed to the plate 28 and is provided adjacent its periphery with aplurality of spaced rows of pusher vanes 48. The rows of pusher vanes 48have a length slightly less than the distance between the inner arcu'ateplates 34 and 36 and the outer arcuate plate 38. 7

As seen more clearly in FIGURE 1, a driven sprocket A flexible belt orchain 52 extends around the driven sprocket 50 and a driving sprocket54-. The driving sprocket 54 is fixedly secured to a shaft 56 extendingfrom the motor 58. The motor 58 is conveniently mounted on the rear wall26. The chain 52 and sprocket 50 do not require lubrication.

A pair of space'd parallel plates 60 are fixedly secured in anyconvenient manner to the top edge of Wall 22 of the housing 12. A roller62 extends between the plates 60. A flexible belt 64 extends around theroller 62. The belt 64 extends around a driving roller (not shown) whichcauses the belt 64 to move and thereby convey machined parts to thecleaning apparatus 10.

A driven roller 66 is rotatably mounted on a shaft 68. which extendsbetween the fixed inner arcuate plates 34 and 36. A crown-shaped plate76 is fixedly secured intermediate the fixed inner arcuate plates 34 and36. A driving roller 72 is rotatably. supported in any convenient mannerand is rotated by a conventional motor means. A flexible belt 74 extendsaround the rollers 66 and 72, whereby rotation of the driving roller 72causes the belt 74 to convey cleaned machined parts away from thecleaning apparatus 10. These parts are above the vapor zone andtherefore do not require a separate lubrication system. 7 V

The roller 66 and the crown-shaped plate 70 are positioned intermediatethe free upper ends 34' and 36 so that the belt 74 is crown-shaped atthe point where the pusher vanes 48 move the clean machined partsthereon for conveyance away from the cleaning apparatus 10. The belt 74is caused to assume a crown-shape between the ends 34- and 3 6 so thatthe clean machined parts will be positioned at the middle area of thebelt 74 before the machined parts move out of the influence of therotating pusher vanes 48. In order to attain this result, the speed ofbelt 74 must be correlated with the speed of the vanes 48.

The wall 18 is provided with an opening 76 and the fixed plate 23 isprovided with an opening 78 through which the belt 74 extends. Theopenings 76 and '78 are of sufiicient size so as not to interfere withthe clean machined parts being conveyed on the belt 74.

An immersion chamber 80 is provided within the lower portion of thehousing 12. The immersion chamber 80 contains a cleaning solvent such astrichlorethylene or the like. A vapor zone 82 is maintained above thecleaning solvent in the immersion chamber 89. The interface between thevapor zone 82 and the solvent in the immersion chamber 80 is designatedas 83. The upper limit of the vapor zone 82 is determined by the coolingcoils 84 which extend around the inner periphery of the housing 12 atthe level of the shelf 20.

A sump 86 is provided within the housing '12 and a heating coil 88 ispositioned Within the sump 86. The heat from the heating coil 88vaporizes the solvent within the sump 86 so as to maintain the vaporzone 82. The solvent within the sump 86 is maintained separate from thesol-vent within the immersion chamber 80 by an upright wall 89.

A plurality of ultrasonic transducers 90 extend from the inner surfaceof the plate 28 and are positioned between the ends 34" and 36" of theinner arcuate plates 34 and 36 respectively. The transducers 90 radiatedownwardly toward the inner surface of the outer plate 38 so as togenerate cavitation only in that portion of the solvent through whichthe machined parts will pass. It will be noted that the lower portion ofthe outer arcuate plate 33 is provided with a plurality of small holesor slots 91 so that contaminate may settle onto the bottom wall 24 ofthe housing 12.

The outer arcuate plate 38 is provided with a hole in the vapor zone 82through which extends a nozzle 92. The nozzle 92 is connected to a pump(not shown) which in turn is connected to a trough (not shown) locatedbelow the cooling :coils 84. The nozzle 92 directs a stream of cleandistillate at the machined parts after they have emerged from thesolvent in the immersion chamber 84). The nozzle 92 is positioned so asnot to interfere with the machined parts being pushed along the innersurface of the plate 38. If desired, the nozzle 92 may be in plate 36.

A platform 94 is secured to the front wall 22. A condenser 96 issupported on the platform 94. The condenser 96 has its inlet side incommunication with the interior of the housing '12 above the vapor zone82 by means of a conduit 98 which may be a manifold conduit. The outletside of the condenser 96 is connected to the inlet side of a fan or pump160'. A return condensate conduit 102 extends from the condenser 96 to alower portion of the housing 12 in the area of the immersion chamber811.

. The outlet side of the fan 100 is connected to a'conduit 102. Theconduit 102 is uninsulated and extends along wall 14 to the wall 26 asshown more clearly in FIGURE 3. The conduit 102 may be supported bybrackets 106. The conduit 162 may terminate in a pair of parallel branchconduits F168 and Md. The conduits 1G8 and are at substantially the samelevel as the conduit 98.

The operation of the cleaning apparatus 18 of the present invention isas follows:

Machined parts having adhering contaminate are posi tioned on the belt64 in any convenient manner. Movement of the belt 64- causes themachined parts to fall off the belt 64 directly onto the outer surfaceof the inner arcuate plate 34. The machined parts to be cleaned aremoved along the outer surface of the inner arcuate plate 34 by thepusher vanes 48. As the pusher vanes 48 move the machined parts throughthe vapor zone 82, the machined parts tumble due to gravity so that theyare moved through the solvent in the immersion chamber 80 on the innersurface of the outer arcuate plate 38. As the machined parts movethrough the vapor zone 82, they are degreased. As the machined partspass through the solvent in the immersion chamber 8i) on the innersurface of the outer arcuate plate 38, they are subjected to thecavitation generated by the ultrasonic transducers 99. At the lowermostpoint of the plate 38, the machined parts are out of the control of thevanes 48 for a short period of time. The ultrasonic transducers 90 aremounted directly above and adjacent the machined parts when they passout of the control of the pusher vanes 48. At this point, the machinedparts are directly subjected to the cavitation generated by thetransducers 9d. The spacing between the pusher vanes 48 prevents anystructure from interrupting the cavitation. Any contaminate removed fromthe machined parts will settle onto the inner surface of the outerarcuate plate 38 and pass through the holes or slots 91. Thereafter, thesediment will not be in a position to interfere with the cavitationgenerated by the ultrasonic transducers 9%.

While still being subjected to the cavitation generated by thetransducers 99, the machined parts are moved by the pusher vanes 48along the inner surface of the outer arcuate plate 33 out of thecavitation zone and through the vapor zone 82 on the lefthand side ofFIGURE 2. As the machined parts pass through the vapor zone 82, they aresubjected to a stream of clean distillate by the nozzle 92. The streamof distillate from the nozzle 92 rinses the machined parts. As themachined parts pass through the vapor zone 82, the temperature of theparts is increased so that the parts may dry more readily.

As the machined parts pass out of the vapor zone 82., they tumble due togravity so that they are now being pushed along the outer surface of theinner arcuate plate 36. As the machined parts are moved beyond the upperend 36' of the inner arcuate plate 36, they are deposited on the belt74. The pusher vanes 43 continue to push the machined parts so that themachined parts are at the middle portion of the belt 74 before themachined parts pass out of the influence of the pusher vanes 48. Inorder that the pusher vanes may continue to have an influence on themachined parts, the belt 74 is caused to have a crown-shape in the areabetween the upper ends 34 and 36' by the crown-shaped plate 70. The belt74 conveys the clean machined parts away :from the cleaning apparatus 10to any desired location. For purposes of illustration, the belt 74 isshown in FIGURE 1 as extending around rollers 66 and 72 which aresupported on the housing 12. if desired, the driving roller 72 may besupported at a location spaced from the cleaning apparatus '10.

A mixture of air and vaporized solvent existing above the vapor zone 32will be sucked into the condenser 96 due to the fan 100. The condenser96 separates the mixture into liquid solvent and cool air. The liquidsolvent is returned to the immersion chamber by conduit 102. The coolair will be forced by the fan 1% to flow through the conduit 1% and bedischarged through the conduits 1&8 and 110.

The cool air discharging from the conduits 103 and 110 is directedtoward the cleaned machined parts thereby accelerating the drying ofentrained solvent. The temperature of the air returned by the conduits108 and 110 is lower than the ambient temperature. Hence, the returnedair will settle into the housing 12 above the vapor zone 82 rather thanrise out of the open top of the housing 12. Due to the low capacity ofthe fan 101i, little or no ambient air from above the housing 12 will besucked into the conduit 98. Likewise, little or no vaporized solventfrom the vapor zone 82 will be sucked into the conduit 98. I have foundthat a manifold conduit arrangement such as the provision of conduits98, 108 and 110 becomes increasingly desirable as the distance betweenthe Walls 22 and 26 increases. The distance between these walls issometimes less than two feet, then a single port in each wall issufficient. The same relationship exists with respect to the length ofthe walls 22 and 26. When the length of these walls exceeds two feet, amanifold arrangement is more eflicient. The most surprising feature ofthe present invention is the fact that there is substantially no fumesin the area of the apparatus 16 and the amount of solvent lost due toescape of vaporized solvent is extremely small even though the housing12 lacks a top wall.

As the cleaning apparatus 10 is utilized, there is a gradual build-up ofcontaminate and sediment within the immersion chamber on the bottom wall24. A drain (not shown) may be provided so that the solvent within theimmersion chamber 80 and the sediment may be removed. The cleaningapparatus 10 includes few moving parts so that it is not susceptible toneeding any major repairs or overhauling. If desired, wall 26 or aportion thereof may be made removable so as to provide access to theinterior of the housing 12.

It should be noted that the cavitation effect concentrates at certainlevels called power nodes wherein the most effective cleaning isobtained. .The-arcuate path of the parts to be cleaned assures that theparts pass through the power nodes.

The present invention prevents delicately machined parts such as ballbearings from impinging against one another since they are separated bythe vanes 48. The vanes 48 may be made of a material which is softerthan the ball bearings so as to avoid flat spots which may be caused bythe drop from the belt 64.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

1 claim:

'1. In a cleaning apparatus for :degreasing machined parts comprising ahousing having an open top, a mechanical means within said housing forreceiving parts to be cleaned and for moving the parts through a portionof said housing adapted to contain a cleaning solvent, means coupled tosaid housing at a point above the level of the solvent adapted to becontained in said portion of said housing for removing a mixture of airand vaporized solvent and returning the air of said mixture in a coolstate to said housing at substantially the same level at which themixture was removed, whereby the amount of solvent lost due tovaporization and escape of fumes through the open top of said housingare reduced.

2. In an apparatus in accordance with claim 1 wherein said mechanicalmeans includes fixed inner and outer plates, a rotary member havingpusher vanes disposed between the inner and outer plates, and meanscoupled to said rotary member for rotating the same.

'3. In an apparatus in accordance with claim 1 including means withinsaid housing providing a vapor zone below the level at which the mixtureof air and vaporized solvent is removed by said last mentioned means.

4. In a cleaning apparatus in accordance with claim 1 wherein said lastmentioned means includes a fan having its inlet side coupled to theinterior of said housing through a condenser, a conduit extending fromthe opposite side of said fan, and said conduit being connected to saidhousing and operatively associated with said mechanical means so thatcool air may be returned to said housing at a point wherein it may bedirected at machined parts which have been conveyed through the solventadapted to be disposed Within said portion of said housing.

5. In an apparatus in accordance with claim 1 wherein said lastmentioned means includes a first manifold structure, a condenser, saidcondenser being in communication with said housing through said firstmanifold structure, a fan, the inlet side of said fan being incommunication with said condenser, a second manifold structure, aconduit having one end coupled to the output side of said fan, the otherend of said conduit being References Cited in the file of this patentUNITED STATES PATENTS 1,399,415 Taliaferro Dec. 6, 1921 1,725,059 ColbyAug. 20, 1929 2,860,646 Zucker Nov. 18, 1958 3,019,800 Rand Feb. 6, 1962

1. IN A CLEANING APPARATUS FOR DEGREASING MACHINED PARTS COMPRISING AHOUSING HAVING AN OPEN TOP, A MECHANICAL MEANS WITHIN SAID HOUSING FORRECEIVING PARTS TO BE CLEANED AND FOR MOVING THE PARTS THROUGH A PORTIONOF SAID HOUSING ADAPTED TO CONTAIN IN SAID VENT, MEANS COUPLED TO SAIDHOUSING AT A POINT ABOVE THE LEVEL OF THE SOLVENT ADAPTED TO BECONTAINED IN SAID PORTION OF SAID HOUSING FOR REMOVING A MIXTURE OF AIRAND VAPORIZED SOLVENT AND RETURNING THE AIR OF SAID MIXTURE IN A COOLSTATE TO SAID HOUSING AT SUBSTANTIALLY THE SAME LEVEL AT WHICH THEMIXTURE WAS REMOVED, WHEREBY THE AMOUNT OF SOLVENT LOST DUE TOVAPORIZATION AND ESCAPE OF FUMES THROUGH THE OPEN TOP OF SAID HOUSINGARE REDUCED.